1. Field of the Invention
The present invention relates to image signal processing that enables a user to discriminate a desired object from an entire image captured with an electronic endoscope.
2. Description of the Related Art
An electronic endoscope, having an imaging device at the end of an insertion tube, is used for medical examinations, industrial examinations, and so on. Light is irradiated from the end of the insertion tube to illuminate an object for observation. An optical image formed by the reflected light is captured by the imaging device, and the captured image is displayed on a monitor.
A medical endoscope is used for identifying abnormal tissue or a lesion of internal organs. The appearance of abnormal tissue or a lesion is different from that of healthy tissue. Based on the user's observation, the abnormal tissue or lesion can be identified.
However, the outer appearance of a lesion that exists deep under the surface of an organ is not clearly defined from that of healthy tissue. Therefore, it is often difficult to distinguish such a lesion.